On October 8, 2025, Regeneron Pharmaceuticals announced that the U.S. Food and Drug Administration (FDA) approved Libtayo (cemiplimab-rwlc), a PD-1 inhibitor, as the first and only immunotherapy for adjuvant treatment of adult patients with cutaneous squamous cell carcinoma (CSCC) at high risk of recurrence following surgery and radiation. This approval, evaluated under Priority Review, is grounded in data from the pivotal Phase 3 C-POST trial, published in the New England Journal of Medicine and presented at ASCO 2025.
The trial demonstrated a significant 68% reduction in the risk of disease recurrence or death (hazard ratio: 0.32; 95% CI: 0.20-0.51; p<0.0001) compared to placebo, meeting the primary endpoint of disease-free survival. Libtayo, already the standard of care for advanced CSCC, now offers a transformative option for earlier-stage patients with high-risk CSCC, addressing a critical unmet need where no prior immunotherapy was approved.
The safety profile in the adjuvant setting aligns with Libtayo’s known profile in advanced cancers, with common adverse reactions including rash, pruritus, and hypothyroidism, and serious adverse events like pneumonia and diarrhea occurring in 18% of patients. CSCC, one of the most common skin cancers with approximately 1.8 million U.S. cases annually, often has favorable outcomes with surgery and radiation, but high-risk cases face significant recurrence risks.
This approval establishes Libtayo as a versatile PD-1 inhibitor, with five FDA-approved indications across various cancers. Regeneron’s Libtayo Surround™ program supports patients with financial and educational resources. An additional regulatory application is under review in the European Union, with a decision anticipated by mid-2026. This advancement underscores Regeneron’s commitment to innovative cancer therapies, leveraging its VelocImmune technology to address critical needs in non-melanoma skin cancers.
